FR2825766A1 - THERMAL EFFECT CONTROLLED RELEASE MECHANISM - Google Patents

Abstract

The present invention relates to a device forming a controlled release mechanism, characterized in that it comprises two structural elements (100, 200) capable of relative displacement, and a locking means (300) capable of initially prohibiting the relative displacement between the two structural elements (100, 200), in which the locking means (300) comprises in combination at least one assembly comprising on the one hand threads (310) and on the other hand a complementary thread (320), linked respectively to the two structural elements (100, 200), and a low melting point material (330) disposed at least on part of the interface between two parts respectively linked to the two structural elements (100, 400), of preferably between the threads (310) and the complementary internal thread (320), to prevent the release of the locking means (300), and consequently of the structural elements (100, 200), before melting of said material.

Description

The present invention relates to the field of mechanisms to

  release controlled by a thermal effect.

  The present invention relates in particular, but not exclusively, to pyromechanisms, that is to say the field of mechanisms controlled by a pyrotechnic effect. Many effect-controlled release mechanisms

  have already been proposed.

  The present invention now aims to provide a device having properties superior to those of prior devices

1 0 known.

  The object of the present invention is in particular to provide a

  device with high mechanical strength at rest.

  The aforementioned aims are achieved within the framework of the present invention by means of a device comprising: 15. two structural elements capable of relative displacement, and a blocking means capable of initially prohibiting relative displacement between the two structural elements, in which the locking means comprises in combination: at least one assembly comprising on the one hand threads and on the other hand an additional thread, respectively linked to the two structural elements, and a material with low melting point disposed at least on one part of the interface between two parts linked respectively to the two structural elements to prevent the release of the locking means, and by

  consequent structural elements, before melting of said material.

  According to another advantageous characteristic of the present invention, the material with a low melting point is arranged at least on a part of the interface between the threads and the complementary thread to prevent the release of the locking means, and consequently of the elements

  of structure, before melting of said material.

  Other features, objects and advantages of the present invention

  will appear on reading the detailed description which follows, and

  look at the accompanying drawings, given by way of nonlimiting examples and in which: FIG. 1 represents a schematic view, in longitudinal axial section, of a device according to a preferred embodiment of the present invention, FIG. 2 represents a similar partial view, in longitudinal axial section, of an alternative embodiment according to the present invention, and FIGS. 3, 4, and 5 represent three alternative embodiments according to

the present invention.

  We can see in Figure 1 attached a device according to the present invention, which comprises: a first structural element 100, a second structural element 200 and

15. a blocking means 300.

  The locking means 300 is formed by the combination of at least one assembly comprising on the one hand threads 310 and on the other hand a complementary taraudoge 320, connected respectively to the two structural elements 100 and 200, and 20. d ' a material 330 with a low melting point placed at least on a part of the interface between the threads 310 and the complementary thread 320 to prevent the release of the locking means 300, and consequently

  structural elements 100 and 200, before melting of said material 330.

  Structural elements 100 and 200 can be the subject of

many embodiments.

  According to the particular embodiment illustrated in Figure 1 attached, these two elements 100 and 200 are formed globally of concentric cylindrical structures centered on an axis O-O and they are moreover capable of relative translation along the axis O-O after

  release of the blocking means 300.

  More precisely, the element 100 has the general shape of a central rod, while the element 200 has the general shape of a jacket.

  cylindrical which partially surrounds the rod 100.

  According to Figure 1, the element 200 is formed by assembling different parts 202, 204, 206, 208, 210. However, the invention is not limited to this particular geometry. Said exhibits 202 to 210 will not be

  therefore not described in more detail below.

  It will simply be noted that preferably the parts 202 to 210

  define a closed chamber 220 on one end of the rod 100.

  The structure thus formed can constitute a cylinder type assembly in which the rod 100 forms a piston capable of relative translation.

  controlled with respect to the jacket 200 which forms the cylinder body.

  Sealing means, such as O-rings, can be inserted between the two elements 100 and 200. Such sealing means can be housed, for example, in annular grooves 130, 230, 232 formed in one or the other. other of the two elements 100, 200 and leading to

the interface between them.

  The invention is however not limited to devices in which the two structural elements are only capable of relative translation. Thus, for example, the translational movement of the rod 100 can be replaced or transformed into any other suitable movement, for example an oblique movement or a movement relative to rotation relative to the element 200, using a screw system. / nut or equivalent. According to the representation given in FIG. 1, the threads 310 are provided on the external surface of a section of the rod 100. The internal thread 320 is provided on the internal surface of a nut 340. And the element 200 is in

  support against the nut 340, via a spacer 240.

  The spacer 240 is formed by a sleeve centered on the axis O-O.

  Low-melting material 330 can be the subject of many

embodiments.

It can be a metal.

  In this context, preferably, the material 330 is chosen from the group comprising: - Bi50 / Pb28 / Sn22 (for a melting temperature of the order of 95-110 C) or - In (for a melting temperature of l '' order of 156 C) or - Sn or Sn85 / Zn15 (for a melting temperature of the order of 200 250 C) or - Pb82.5 / Cd17.5 or - Pb96 / Sb4 (for a melting temperature of l '' order of 250-300 C). The use of a metal to form the material 330 leads to a

brazing of the nut 340.

  However, the invention is not limited to a metal. The material 330 may be formed from any other heat-fusible material capable of fulfilling the same function, for example a paraffin-based material or a

eutectic alloy.

  The threads 310 and the complementary thread 320 are preferably formed of reversible threads, that is to say of threads having a sufficient pitch so that a traction exerted on the nut 340 eVou on the rod

100 is driving.

  By way of nonlimiting example, for an internal diameter of nut of

  17.5 mm, we can provide 15 threads in 15 mm steps.

  Heating element capable of melting on demand

  material 330 can be the subject of numerous embodiments.

  According to a preferred embodiment, it is a block of

  pyrotechnic material 150 integrated into the structure.

  More precisely still according to the preferred embodiment illustrated in FIG. 1 attached, the pyrotechnic material 150 is placed in an axial blind chamber 152 formed in the rod 100 and which

opens into room 220.

  The pyrotechnic composition 150 can thus be formed from: - Al + Fe2O3 or - Mg + Fe203 or -Al + CuOou

-Mg + CuO.

  The operation of the device according to the present invention, which

  has just been described, is essentially the following.

s

  At rest, the nut 340 is blocked on the rod 100 by the material 330.

  The shirt 200 is in abutment against the spacer 240, it even in abutment

against nut 340.

  Therefore the rod 100 can not be biased towards the outside of the shirt 200, or to the left, relative to the shirt 200, according

  the illustration given in figure 1.

  To release the device, simply implement the composition

  pyrotechnic 150 or any equivalent heating means.

  After the material 330 has melted, the nut 340 is released.

  A displacement of the rod 100 relative to the nut 340 and to the

  shirt 200 is then possible under the effect of an adequate driving force.

  This can be formed by the gases developed by the composition

  pyrotechnic 150 itself in room 220.

  Note that during this movement, if the clearance between the threads 310 and the internal thread 320 allows, the material 330 is laminated at

  the interface between the threads 310 and the internal thread 320.

  This rolling makes it possible to slow down the relative movement between the elements 100 and 200. This gives a controlled release of the

  mechanical constraints of the structure.

  An alternative embodiment has been illustrated in FIG. 3 designed specifically to reinforce a braking effect by rolling the material 330, during the melting of the latter. We find in Figure 3 the rod 100 in engagement, by a thread 310/320 initially blocked by a material 330 embedding the threads, with the nut 340. However the nut illustrated in Figure 3 defines a housing 342 able to accommodate a reserve 331 of material 330, which housing 342 opens to the outside via a passage of calibrated section 343. The housing 342 is defined in part by a recess formed on the rod 100. Thus, after melting of the material 330, a relative displacement between the elements 100 and 200 requires a reduction in the volume of the housing 342 which results in a rolling of the material 330 by the

passage 343.

  It will be noted that the spacer makes it possible to thermally insulate the outer jacket 200 relative to the zone of the pyrotechnic composition 150

  likely to be brought to high temperature.

  The present invention finds particular, but not exclusively, application in the field of the space industry, for example on the

launchers or satellites.

  Of course the present invention is not limited to the particular embodiment which has just been described, but extends to all variants

conform to his spirit.

  In particular according to an advantageous variant of the present invention, means may be provided which avoid relative rotation between

  the spacer 240 and the nut 340 during the implementation of the device.

  According to a first embodiment, as illustrated in FIG. 2, such means can be formed of two superimposed engaged nuts, of inverted pitch: 340 and 345. A first nut 340 is engaged with the threads 310 of the rod 100 It is itself provided with threads on its external surface, in engagement with the second nut 345. The latter serves as a support for the spacer 240. The threads of the two nuts 340 and 345 are initially blocked using a material with a low melting point. The pitches of the two nuts 340 and 345 can be identical. However this characteristic

is not imperative.

  According to a second embodiment, a ball bearing or

  equivalent, can be inserted between the nut 340 and the spacer 240.

  The combination of the low-melting material 330 and the threads 310/320 makes it possible, within the framework of the present invention, to benefit from a

  high mechanical strength, at rest of the device.

  There is illustrated in Figure 4 an alternative embodiment in which we find the rod 100 engaged by thread 310/320 with a nut 340 defining a housing 342 adapted to receive a reserve 331 of material 330 at low melting point. However according to the variant of Figure 4, the material 330 which blocks the mounting is not placed at the level of the threads 310/320, but at the level of an interface 350, cylindrical of revolution, formed between the external surface of the rod 100 and the internal surface of

  the nut 340, on a separate section of the threads 310/320.

  Another embodiment has been illustrated in FIG. 5 in which the rod 100 is found in engagement by thread 310/320 with a nut 340. Here the nut 340 does not define a reserve for the material with a low melting point, as is the case in FIGS. 3 and 4. However, according to the variant of FIG. 5, as in FIG. 4, the material 330 which blocks the assembly is not placed at the level of the threads 310/320, but at the level of an interface 350, cylindrical of revolution, formed between the external surface of the rod 100 and the internal surface of the nut 340, on a section

separate from nets 310/320.

  Of course according to still other variants, provision may be made initially to block the assembly using a material with a low melting point 330 present both at the level of the threads 310/320 and at the level of a

cylindrical interface 350.

Claims (15)

R E V E N D I C A T I O N S   1. Device forming a controlled release mechanism, characterized in that it comprises: 5. two structural elements (100, 200) capable of relative movement, and a locking means (300) capable of initially prohibiting the relative movement between the two structural elements (100, 200), in which the locking means (300) comprises in combination: 10. at least one assembly comprising on the one hand threads (310) and on the other hand a complementary thread (320 ), linked respectively to the two structural elements (100, 200), and a material with a low melting point (330) arranged at least on a part of the interface (310/320, 350) between two parts linked respectively to the two structural elements (100, 400) to prevent the release of the locking means (300), and therefore structural elements (100, ), before melting said material.   2. Device according to claim 1, characterized in that the material with a low melting point (330) is arranged at least on part of the interface between the threads (310) and the complementary thread (320) to prevent the release of the locking means, and consequently of the elements   structure (100, 400), before melting said material (330).   3. Device according to one of claims 1 or 2, characterized by the   causes the internal thread (320) to be formed on a nut (340).   4. Device according to one of claims 1 to 3, characterized by the   fact that a spacer (240) is interposed between one of the elements of   structure (200) and the locking means (300).   5. Device according to one of claims 1 to 4, characterized by the   causes the low melting point material (330) to be made of a metal.   6. Device according to claim 5, characterized in that the material with low melting point (330) is chosen from the group comprising: - Bi50 / Pb28 / Sn22 (for a melting temperature of the order of 95-110 C) or - In (for a melting temperature of around 156 C) or - Sn or Sn85 / Zn15 (for a melting temperature of around 200 250 C) or Pb82.5 / Cd17.5 or - Pb96 / Sb4 (for a melting temperature of the order of 250-300 C).   7. Device according to one of claims 1 to 4, characterized by the   causes the low melting point material (330) to be made of   based on paraffin or a eutectic alloy.   8. Device according to one of claims 1 to 7, characterized by the   fact that the threads (310) and the additional thread (320) are formed of reversible threads, that is to say threads having a pitch sufficient for traction to be driven, after melting the material at low melting point (33o ).   9. Device according to one of claims 1 to 8, characterized by the   that it further comprises a heating means (150) capable of causing   selectively melting the low melting point material (330).   10. Device according to claim 9, characterized in that the heating element (150) is formed of a pyrotechnic material (150) integrated into the structure.   11. Device according to one of claims 1 to 10, characterized by the   fact that it comprises means (340, 345) preventing relative rotation between the locking means (300) and one of the structural elements (200) during the implementation of the device.   12. Device according to claim 11, characterized in that the means (340, 345) preventing relative rotation comprise two nuts   in overlapping engagement, with inverted steps (340, 345).   13. Device according to claim 11, characterized in that the means (340, 345) avoiding relative rotation comprise a bearing with balls or equivalent.   14. Device according to one of claims 1 to 13, characterized by the   fact that at least one of the structural elements (100, 400) defines a housing (342) capable of accommodating a reserve (331) of material (330) with low melting point, which housing (342) opens onto the exterior by a passage of calibrated section (343) and is adapted to reduce its volume during a relative displacement between the structural elements (100, 200) so that this displacement causes a rolling of the material (330) by the passage (343).   15. Solon device one of claims 1 to 14, characterized by the   includes material (330) having a low melting point at a   interface (350) different from the threads (310/320).